Seriously? I guess this is what the companies are targeting. The people who are not well versed with the SSD space. Can't blame you guys.
Anyway, NVMe SSDs are quite fast as it is. It's just that those are based on PCIe Gen 3. PCIe gen 4 are very very new. Which explains its higher price tag during this period of time. Over time, the price of the NVMe SSDs will begin to drop as there is now more market segment for the PCIe gen 4 NVMe drives thanks to both PC and PS5 utilizing it.
Cut the story short, there are a few PCIe gen 4 NVMe SSDs that meet the requirement of the PS5. But will I recommend using it, not yet. We are still in the PS5's early days. Give it time for reviewers to test out the best SSDs to fit into the PS5. In the mean time, you can just utilize the internal memory of the PS5 and upgrade when there are more reviews on the best drives that are not Sony certified so that it will be priced cheaper without any unnecessary price gouging from the clueless people.
1 example of a reasonable 500GB SSD that suits the criteria of the PS5 though I would not recommend buying a 500GB SSD.
https://www.amazon.sg/Seagate-Firecuda-Performance-Internal-ZP2000GM3A002/dp/B07ZPRQ4YM/
As you can see, the price is in SGD$169.24. Way lesser than the supposed 'US$150' for the same 500GB SSD.
If you want an SSD that is way beyond even the PS5's internal SSD, look at the Samsung's newer 980 Pro NVMe SSD. This has speeds of up to 7000MBps. Definitely way faster. But the price is currently way higher too. But over time, by the time we need to upgrade the PS5 storage, the price might have come down a little. Look forward to it.